This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The HARC (HIV Accessory and Regulatory Complexes Center) at UCSF is directed by Prof Al Frankel and aims to develop new tools and methods to create a complete picture of HIV-host cell interactions occurring during the early phases of the virus's life cycle. The aim of the project with the UCSF Mass Spectrometry Facility is to build HIV-host protein interaction maps of HIV complexes in uninfected and infected states. Affinity tagged proteins from uninfected and HIV-infected Jurkat cells will be isolated and the associated proteins will be identified by MALDI-TOF and LC/MS/MS mass spectrometry. Approximately 15 HIV-encoded proteins will be expressed, with some mutant variants. Additionally, affinity-tagged versions of selected host proteins found to interact with the HIV proteome will be generated and complexes will be purified from infected cells to confirm that the interactions and physiologically relevant. The wider aim of the work is the generation of well-characterized complexes for structural studies.